Indexing grinding fixture



May 13, 1952 R. STEGALL 2,596,304

INDEXING GRINDING FIXTURE Filed Sept. 16, 1949 2 SHEETS-SHEET 1 IN V EN TOR.

Rov STEGALL, BY

May 13, 1952 R. STEGALL INDEXING GRINDING FIXTURE 2 SHEETS-SHEET 2 Filed Sept. 16, 1949 INVENTOR. ROY STE GA LL.

ATTO 2 N a s.

Patented May 13, 1952 v UNITED STATES PATENT OFFICE I 2,596,304 INDEXING GRINDING FIXTURE Roy Stegall, Chicago, Ill. Application September 16, 1949, Serial No. 116,154 f 2 Claims, 1

This invention relates to work-holding fixtures,

and more particularly to a fixture to be used with a grinding machine to index and grind a work piece to polygonal shape with its faces parallel to a predetermined axis.

It is among the objects of the invention to provide an improved work-holding fixture in which a work piece can be exactly centered and which can be mounted on a grinding machine and operated to present Work piece faces in predeter mined angular relationship to each other to the grinding wheel of the machine and maintain such faces exactly parallel to the axis on which the work piece is centered, which is operative to position the work piece for grinding one or more pair of mutually parallel faces thereon, so that work pieces of different shapes can be produced including work pieces of square or rectangular, hexagonal, octagonal and other polygonal crossseotional shapes, and which is simple in construction, is adjustable to receive work pieces of different sizes, is easy to mount on a conventional grinding machine, and is economical to manufacture.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawings, wherein:

Figure 1 is a top plan view of a fixture illustrative of the invention;

Figure 2 is a front end elevation of the fixture;

Figure 3 is a rear end elevation of the fixture;

Figure 4 is a longitudinal cross-section on an enlarged scale on the line 4-4 of Figure 1;

Figure 5 is a side elevation on an enlarged scale of a fragmentary front portion of the fixture;

Figure 6 is a cross-section of a fragmentary portion of the fixture taken on the line 6-5 of Figure 4; and

Figure 7 is an elevational view substantially on the plane of the line I-JI of Figure 4.

With continued reference to the drawings, the work-holding fixture comprises, in general, a base II] of generally U-shaped formation having a pair of spaced-apart, apertured lugs or legs, a tail stock socket II mounted in one of the legs and projecting outwardly therefrom, a tail stock I2 adjustably threaded into the socket I I, a head plate I3 rotatably mounted in the other lug or leg of the frame, a head stock I4 mounted in the head plate I3, a handle I5 secured to the head plate and positioned at the outer side of the frame leg in which the head plate is journaled, a locking pin I6 slidably mounted in a bore in the handle I5 and selectively engageable in a series of apertures provided in the head-plateecarrying leg of the frame and arranged 'at substantially equal angular intervals in a, circle centered on the axis of rotation of the head plate, and. a workpiece-engaging dog I'I engageable with a work piece centered between the tail stock I2 and the head stock I4 and connected to the head plate I3 for rotating the work piece with the head plate.

The base ID has a rectangular bight l8 formed of suitable material, preferably of a magnetic character, and of sufficient weight and thickness so that the base can be held on a magnetic grinding machine table. Ali upstanding leg or lug I9 is provided at one end of the big'ht I8 and is of rectangular shape with an extension 20 at the midlength location of its upper edge in which extension an aperture 2I is provided to receive the tail stock socket I I.

The tail stock socket I I has a reduced cylindrical portion 22 secured in the aperture 2! and terminating in an angular shoulder which bears against the outer face of the extension 20 sur rounding the aperture M to positively locate the socket relative to the frame leg I9. The socket II is an elognated, tubular body having a bore therethrough and a screw-threaded counterbore opening to the end of the socket opposite the end secured in the frame leg I9.

The tail stock I2 is an elongated pin having a conically-pointed inner end 23 engageable with the work piece 24 and having on its opposite end a knurled head 25. Adjacent the head 25 the tail stock is provided with external screw threads threadable into the screw-threaded counterbore of the socket II, so that the tail stock is adjustable longitudinally of the socket upon rotation of the tai1 stock by the knurled head 25. A knurled lock nut 26 is threaded onto the tail stock at the outer end of the socket for locking the tail stock in adjusted position relative to the socket.

At its end opposite the lug I9, the frame bight I8 is provided with an upstanding leg or lug 21 of elongated, rectangular shape which extends from the bight I8 2. distance greater than the leg I9. This leg 21 is provided with an aperture 28 which has a common center line with the aperture 2|, but is larger than the aperture 2 I. The leg 2'! is also provided with a plurality of apertures 29 arranged at substantially equal angular intervals around a circle centered on the center line or axis of the aperture 28. The apertures 29 are prefer" ably so spaced that two of them are centered on a line perpendicular to the frame bight I3 and extending through the center line of theaperture 28, and two others, disposed at respectively-opposite sides of the aperture 28, are centered on a 7 line perpendicular to the first-mentioned line and also passing through the center line of the aperture 28 with the remaining apertures arranged in pairs respectively disposed at opposite sides of the aperture 28 and centered on lines passing through the center line of this aperture.

The head plate [3 comprises a flat disc 36 having an elongated notch 31 opening to the periphery thereof and having onone side a concentric, cylindrical boss; or hub 32 journaled in the aperture 28 and provided with a concentric aperture or bore 33.

The handle l comprises a crank having a circular end portion 34 of substantially the same diameter as the diameter of the hub 33 of th head plate, a short shaft 35 projecting radially from one side of the portion 34 and a cylindrical handle 36 projecting perpendicularly from the.

ture 29 and the dog I! surrounding the work piece with its pin 41 engaged in the notch 3| of the head plate, the work piece is rotated to a position such that one of the faces thereon to be ground flat is disposed directly below the grinding wheel 5|] of the grinding machine, the

upon the. locking pin I6. isreleased and the crank I5 rotated through 180 degrees, the pin reengaged in the corresponding aperture 29, and

thetabie again operated to pass the work piece beneath the grinding wheel. After the fixture and: work piece have been returned to their origor 1 which. liqahl wash th k n n 6-. hi qk us. Pie qm r s s en. lq' l c in i s ank. '3 ari a nur e hea ecur on h shank at e Q i t. nd the a d T iis kin in s ele ve neab e e ures 29, by li it w r 1y and outwardly of the handleiiii, i

The crank L5, is. secured to the. hub ofthe head plate by. suitable means, such as thetwo cap. screws 39, particularly illustrated in Figure 6, extending through registering apertures inthe circular portion of the crank and into screwthreaded wells or bores in the'hub 32, and two dowel pins 40, particularly illustratedin Figure 4, which are centered on a line substantially perpendicular to a line extending through the centers of the screws 39 and which also extend through apertures. in the circular portion of the crank and into wells or recesses provided in the hub 32.

The circular portion of the crank is provided with an aperture of the same size as the aperturein the hub of the head plate and registering with the hub aperture, and the tail stock is comprises a cylindrical shank 4!. received in and closely fitting the bore in thehead plate hub 32 and the aperture in the crank Ill and having at one end an annular bead or flange g2 partly received in a counterbore in the head plate at the end of the bore 33 opposite. the crank le. Beyond the shoulder'or flange 42 the head stock is reduced in size. and provided with a comicallypointed end 63 for engagement with the work piece 24, j V

The work-engaging dog I comprisesfa metal ring of square or rectangular cross-sectional shape, having two diametrically-opposed, screwthreaded bores 4A and .45 extending radially therethrough, and a well or recess 46 opening to one side ofthe ring and disposed at substantially 90 degrees from the b.0 4 4 and 4 5. A pin 4'! 'is secured at one. end in the recess 46 and projects perpendicularly from the ring for engagement in the noteh 3|, of they head plate, and set screws 48. and 43. are threaded into the bores 44 and 45, respectively.

In the. use of the fixture, a .work piece 2 4 is centered in the. fixture by adjustably moving the tail stock 12 and engaging the work piece at the opposite ends of a predetermined axis between the tail stock l2 and the head stock IA. The

mar position, the crank I5 is returned to its original position and another cut made on the f rstface, of the work piece. This process may be continued, gradually lowering the grinding wheel toward. the. center of the work piece until the two f aees are properly "ground, determined by heekirs were h ami m e lip r- I o h la aces re de r d OM 1? W i Piece, the locking pin is engaged in another selected one. of theapertures 29 for the first pass or cut, and is then. moved to t e a e ure di p se 1 degrees from the last selected aperture, and a pass or cut made, and this process, is also repeated until the. two additional faces have been brought to the. proper positions as indicated by a micrometer caliper By. continuing this process, as many faces can ground onto the work piece as there are apertures 29 the leg 21 of t e fram and thes fat s W 11 e l on the rotationalaxis bf the work piece a nd substantia11y-:para .1 1 ther to.- H W -Y f all O h faces will not necessarily be the same distance from the. rotational axis of the work piece.

If'it is desired to grind the. faces parallelto a bore orlhole provided through the work piece, the

pointed ends of the head and tail stocks of-the fixture are inserted into respectivelyopposite ends of sueh a hole or bore and the ground faces will then be exactly parallel to such hole or bore in the work piece.

By means of the fixture, the work piece is p ly and p i i qee te an an be essential characteristies Ithereo'f. The present embodiment is, therefore, to. be considered in all V respectsas illustrative. and notrestrictiiifi, .the

ai t k is h n be d by the. 09 s 1 25 to el the ork pi eent r d the tur n with the pin 38 engaged in the uppermost aperscope of the invention being indicated by the appended claims ratherthan'by the foregoing description, and all changes which comewithirl the meaning and. range. of equivalency of the claims are, therefore,intended te'be. embraced therein.

What is claimed is:

1. A workflholding fixture for a grinding machine comprising a base having longitudinally spaced and aligned vertical legs, .a tail stock horizontally mounted through one. of the'legsand longitudinally adjustable relative to the opposing leg, a head plate retatahlyfieurnalled to the inner face of the opposing leg, a headstock dis posed through said headplate and longitudinally aligned with the tailstock, said head plate being rotatable on the head stuck, a crank fixed to the journalled portion oi the head plate to rotate the plate, a m slidably meunted transversel in the crank, said leg being formed with a plurality of transverse apertures concentrically arranged around the head stock and selectively longitudinally alignable with the pin, and a workpiece engaging dog spaced from and engaged with the head plate to rotate therewith.

2. A workpiece holding fixture for a grinding machine comprising a base, a pair of longitudinally spaced and aligned vertical first and second posts on said base, a horizontally disposed longitudinally adjustable tail stock mounted in the first post, a head stock mounted in the second post and longitudinally aligned with the tail stock, a head plate rotatably disposed on the inner face of the second post and having a hub portion rotatable on the head stock and extending through the second post, a crank secured to the hub at the outer face of the second post for rotating said head plate, said second post having a plurality of transverse openings formed therein and concentrically arranged around the head stock, a pin slidably mounted transversely in the 6 crank and selectively engageable in the apertures to latch the head plate against rotation, a work engaging dog adapted to be vertically interposed between the head and tail stocks for engaging a work piece centered between the stocks and means on said dog detachably engaging a means on the head plate for rotation therewith.

ROY S'I'EGALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,395,790 Bernard Nov. 1, 1921 2,341,099 Hellman Feb. 8, 19

FOREIGN PATENTS Number Country Date 111,395 Great Britain Nov. 29, 1917 

